4.4 DATA Statement

The DATA statement assigns initial values to variables and array elements before program execution. It takes the following form:

DATA nlist/clist/[[,] nlist/clist/] . . .

nlist

Is a list containing any combination of variable names, array names, array element names, character substring names, and implied- DO lists. (RECORDs are not allowed in this list.) Elements in the list must be separated by commas.

Subscript expressions and expressions in substring references must be integer expressions containing integer constants and implied-DO variables.

An implied-DO list in a DATA statement takes the following form:

(dlist, i = n1,n2[,n3])

dlist

Is a list of one or more array element names, character substring names, or implied-DO lists, separated by commas.

i

Is the name of an integer variable.

n1, n2, n3

Are integer constant expressions. The expression can contain implied-DO variables of other implied-DO lists that have this implied-DO list within their ranges.

clist

Is a list of constants separated by commas; clist constants take one of the following forms:

c
n *c

c

Is a constant or the symbolic name of a constant.

n

Defines the number of times the same value is to be assigned to successive entities in the associated nlist; n is a nonzero, unsigned integer constant or the symbolic name of an unsigned integer constant.

Rules and Behavior

The DATA statement assigns the constant values in each clist to the entities in the preceding nlist, from left to right, as they appear in the nlist. The number of constants must equal the number of entities in the nlist.

When an unsubscripted array name appears in a DATA statement, values are assigned to every element of that array in the order of subscript progression. The associated constant list must contain enough values to fill the array.

The following list describes the relationship between nlist items and clist items:

• If both the constant value in clist and the entity in nlist have numeric data types, conversion is based on the following rules:

  • If necessary, the constant value is converted to the data type of the variable being initialized.

  • When a bit constant is assigned to a variable or array element, the number of digits that can be assigned depends on the data type of the data item (see Table 2-1). If the constant contains fewer digits than the capacity of the variable or array element, the constant is extended on the left with zeros. If the constant contains more digits than can be stored, the constant is truncated on the left.

• If the constant value in clist and the entity in nlist are both of character data type, the conversion is based on the following rules:

  • If the length of the constant is less than the length of the entity, the rightmost character positions of the entity are initialized with space characters.

  • If the length of the constant is greater than the length of the entity, the character constant is truncated on the right.

• If the constant value in clist is of numeric data type and the entity in nlist is of character data type, the constant and the entity must conform to the following restrictions:

  • The character entity must have a length of one character.

  • The constant must be an integer or bit constant and must have a value in the range 0 through 255.

  When the clist constant and the nlist entity conform to these restrictions, the nlist entity is initialized with the character that has the ASCII code specified by the clist constant. (This behavior lets you initialize a character entity to any 8-bit ASCII code.)

• If the constant value in clist is a Hollerith constant or character constant and the entity in nlist is a numeric variable or numeric array element, the number of characters that can be assigned depends on the data type of the data item (see Table 2-1). If the Hollerith or character constant contains fewer characters than the capacity of the variable or array element, the constant is extended on the right with space characters. If the constant contains more characters than can be stored, the constant is truncated on the right.

Example

In the following example, the first DATA statement assigns zero to all 10 elements of array A and 4 asterisks followed by 2 spaces to the character variable STARS:

INTEGER A(10),  B(10)
CHARACTER BELL, TAB, LF, FF, STARS*6
DATA A,STARS /10*0,'****'/
DATA BELL,TAB,LF,FF /7,9,10,12/
DATA (B(I),  I=1,10,2) /5*1/

The second DATA statement assigns ASCII control character codes to the character variables BELL, TAB, LF, and FF. The last DATA statement uses an implied-DO loop to assign values to the odd numbered elements in the array B.